It's been known for a long time that fire is a natural part of the outback. In northern Australia, many low intensity fires are lit early in the dry season in order to reduce the extent of more damaging wildfires that inevitably occur later in the dry season. But information was needed on what was the best way to go about burning off and the consequences of different types of burning.

So, the World's largest bushfire experiment, covering 250 square kilometres, was lit at Kapalga Research Station in Kakadu National Park. As part of an eight-year study, twelve large areas were set alight and controlled by a group of researchers from Australia's science agency CSIRO, universities and government agencies.

"We tested fires that occurred early in the dry season, about May, fires that were lit late in the dry season around October and they're the highest intensity fires that we can get up here. Fires that were lit progressively through the dry season then no fires at all. Completely unburnt."

Researchers recorded the height of the flames, the intensity and spread of fires lit at these different times of the year. They then studied the effects on streams, plants, animals, including insects, and greenhouse gases.

They found that the savanna ecosystem was highly resilient to fire. And surprisingly, populations of most plants and animal species were not even affected by high intensity fires. Some animals, including the Frilled Neck Lizard, actually decreased in number when there was no burn off at all. Many animals were affected by fire but the intensity of the fire did not appear relevant.

The main implication of the study is that conservation managers need to take more account of how often fire occurs rather than the fire's intensity. The Kapalga fire burning study has revealed that in many parts of the Top End, fires are happening too frequently to sustain healthy populations of many animal species.